TU840 3BSE020846R1 | ABB Redundant Module Termination Unit (MTU)

Overview

The ABB TU840 (Part Number: 3BSE020846R1) is a Redundant Module Termination Unit (MTU) designed for the S800 I/O process automation system. It acts as a passive, high-reliability baseplate engineered to host dual, redundant Optical ModuleBus Modems (TB840 or TB840A), splitting power and managing communication routing downstream to redundant I/O clusters without active electronic points of failure.

Technical Specifications

• Product Type: Module Termination Unit (MTU) for Redundant Configuration
• Model Code: TU840
• Part Number: 3BSE020846R1
• Manufacturer: ABB
• System Compatibility: S000 I/O Family (Connects redundant TB840/TB840A Modems to Redundant I/O)
• Communication Protocol Support: ABB's ModuleBus
• Redundancy Support: Yes (Module Redundancy and Line Redundancy capability)
• Power Configuration Type: Redundant Modems / Redundant I/O via Single Power Input
• Nominal Supply Voltage: 24 V DC (Acceptable range: 19.2 to 30.0 V DC)
• Maximum ModuleBus Power Current: 5 V @ 1.5 A, 24 V @ 1.5 A distribution
• Power Dissipation: 2.0 W maximum
• Rated Insulation / Dielectric Test Voltage: 50 V / 500 V AC
• Acceptable Wire Sizes: Solid/Stranded 0.2 to 2.5 mm² (24 to 12 AWG)
• Recommended Terminal Screw Torque: 0.5 Nm
• Ingress Protection Rating: IP20 (IEC 60529 Compliant)
• Country of Origin: Sweden
• Physical Dimensions: 18.6 cm x 12.4 cm x 4.7 cm (Height includes locking latch)
• Product Net Weight: 0.45 kg

Installation Notes

• Mount the TU840 MTU onto a standard cabinet DIN rail, prioritizing a flat orientation to optimize thermal dissipation.
• Adjust the integrated mechanical keys using a flat screwdriver to match the specific profile of the TB840/TB840A modems prior to module insertion.
• Set the localized rotary cluster address switch to the specific node designation assigned in the system configuration software.
• Terminate field power and communication lines to the compression screw blocks, maintaining the recommended 0.5 Nm torque threshold to prevent loose connections.